Permanent magnet operating mechanism is a mechanical device that uses pulse-electromagnetic force to conduct state conversion, and uses permanent magnet force to facilitate action and maintain state. For example, CN patent No. ZL98220417.5, entitled “A Permanent Magnet Operating Mechanism for Vacuum Switch”, owned by this Applicant, discloses such a permanent magnet operating mechanism. It includes an output shaft, a fixed core on the output shaft, a permanent magnet disposed outside the core, and an impulse coil placed on outside of each end of the permanent magnet respectively. The output shaft extends out from the center of the two impulse coils. The permanent magnet operating mechanism has the features of prompt action, automatic maintaining stabilization of the state upon action, etc., so that it usually acts as the operating mechanism for an electric switch. However, in practice, it is found that during operation, though switch-off/switch-on may be achieved if applying pulses to switch-off coil and switch-on coil respectively, the action noise and electricity consumption may be substantial. Such a permanent magnet operating mechanism, upon satisfying reliable switch-on current condition, the instantaneous closing speed is relatively high, and the noise of switch-on is high; while the instantaneous opening speed is relatively low, and the breaking ability is relatively poor. As to the switch-off/switch-on operation of a vacuum breaker, the best design is: the initial speed of switch-on action is relatively low, upon instantaneous closing, the switch-on pulse peak current reaches a maximum value. This facilitates reducing noise, prolonging the service life of components, and assuring reliable switch-on. The switch-off action shall be quick, especially the instantaneous opening speed. However, during later switch-off period, the acceleration declines, to reduce impact among components, and to reduce voltaic arc at instantaneous opening.